1. Field of the Invention
The invention relates to a method for detecting and localizing a fire and/or the origin of a fire in one or more monitored areas as well as a device for realizing the method.
The invention starts out from a fire detecting device having a sensor for detecting a fire parameter which is fed a representative volume of room or device air through a suction pipe system by means of a suction device such as a fan.
2. Description of Related Art
The term “fire parameter” is to be understood as physical variables which are subject to measurable changes in the vicinity of an incipient fire, e.g. ambient temperature, solid or liquid or gaseous content in the ambient air (accumulation of smoke particles or particulate matter or accumulating smoke or gases) or local background radiation.
Both procedures as well as fire detecting devices of the cited type are known and serve for prompt detecting of fires still in their incipient phase. Typical areas of application are either rooms containing high-quality or important equipment such as, for example, rooms containing computer systems in banks or the like, or even just the computer equipment itself. To this end, representative samples of the room air or the device cooling air are continually extracted, referred to in the following as “air sample.” An appropriate means for extracting such air samples and feeding same to the fire sensor, to the housing of the fire sensor respectively, is a suction pipe system designed as a system of conduits which are mounted, for example, below the ceiling of the room and lead to air intake openings in the housing of the fire sensor and which sucks the air samples in through air suction openings provided in the suction pipe system. An important premise in detecting an incipient fire at its earliest stage is that the fire detecting device continually extracts a sufficiently representative amount of air without interruption to supply the sensor sensing chamber. An applicable sensor here would be, for example, a point-based smoke sensor which measures the light turbidity in a sensor smoke chamber caused by particulate matter, or also a scattered light sensor integrated in the intake path which detects scattered light caused by smoke particles at a center of the sensor.
Methods and devices using a plurality of suction pipe systems to detect and localize sources of fire in one or more monitored areas are known from the prior art and have been developed based on the fact that, for example, it is very difficult for firefighting crews to localize the source of a fire in large halls, office buildings, hotels or ships. One single smoke suction system having a single fire-detecting unit may—subject to national regulations—monitor an area of up to 2000 m2, which may also comprise several rooms. In order to enable an operative alarm site to be quickly localized, requirements have been defined such as those set forth, for example, in Germany's “Guidelines for Automatic Fire Reporting Installations, Planning and Construction” (VdS 2095). Pursuant thereto, a plurality of rooms may only be grouped together into one alarm area when the rooms are adjacent, the access to same can be readily seen at a glance, the total surface area does not exceed 1000 m2, and there are clear visual alarm indicators at the fire alarm monitoring station which, in the event of a fire alarm, indicate the area where the fire is located.
While devices for detecting fire which operate on an aspirative principle, in which a plurality of areas to be monitored are connected by one individual smoke suction system, offer the advantage of the earliest possible detection of fire, there is no guarantee that the site of the fire can be localized in such a commonly-shared smoke suction system monitoring a plurality of areas. This is due to the fact that the individual air samples, each representing the room air from one individual monitored area, are fed to the sensor for detecting a fire parameter after having been mixed together in the jointly-shared suction pipe system. All the sensor can thus establish is that a fire broke out and/or is imminent in one of the areas being monitored. In order to be able to additionally ensure a localization of the seat of the fire in one of said monitored areas, it is usually necessary to feed each air sample extracted from each individual monitored area to another sensor of a separate suction pipe system in order to detect a fire parameter. Yet when monitoring a plurality of monitored areas, this has the disadvantage that the corresponding number of suction pipe systems must be in place, which involves a very complex implementation of the one or more aspirative fire detection system(s) both structurally as well as financially.
FR 2670010 Al discloses alarm boxes which serve to identify the smoke-sucking joint in a branched suction pipe system. These alarm boxes consist of a point-based smoke sensor built into a housing with a cable threading to connect the inlet and outlet pipes and a signal light on its cover. Yet disadvantageous to this construction is that because of their size, design and price, these alarm boxes cannot be employed at each individual air intake opening.
Known further from WO 00/68909 is a method and a device for detecting fires in monitored areas by means of which the source of a fire can be localized. This method utilizes an appropriate device in each monitored area comprised of two crossing pipes, into which one or more fans continually suck in air from the monitored areas through suction openings disposed in the pipes and feed same to at least one sensor for detecting one fire parameter per pipe. The localization of the seat of the fire thereby follows from the responding of the two sensors allocated to the crossing pipes. A plurality of areas is monitored by such pipes arranged as a matrix of columns and rows, where appropriate by one cumulative sensor each for the column and row arrangement. A disadvantage to this known device, however, is the very substantial installation outlay for the matrix-like system of pipes.
Known from the German DE 3 237 021 C2 patent specification is a selective gas/smoke detection system having a plurality of suction lines connected separately to various measuring points in an area to be monitored in order to withdraw samples of air or gas at said measuring points. Here, a gas or smoke sensor connected to these lines reacts to the presence of a specific gas in the sample upon a fixed threshold being exceeded and emits a detection signal which controls an indicator and/or alarm circuit. Shut-off valves which are cyclically and periodically energized in a controlled loop are furthermore arranged on the individual suction lines. Detecting fire with this gas/smoke detection system ensues in that in the absence of a detection signal, the control unit sets the shut-off valves such that all the suction lines are simultaneously in open connection with the sensor, and upon a detection signal being received, switches them over to a sensing mode in which the suction lines are conventionally brought into open connection with the sensor consecutively or in groups. This function for detecting the origin of fire presupposes, however, that the sensor can be brought into connection with each area to be monitored by way of individual and selectively-opened feed lines. This inherently means having to install an extensive system of pipes in order to create these individually selectable connections. Likewise disadvantageous is the high cost of installing the necessary suction lines.
WO 93/23736 further makes known an air pollution/smoke detection device based on a network-like configured suction system having a large number of sampling sites at which gas is extracted from each room to be monitored. This pollution/smoke detection device has a plurality of inlet ports connected to the grid-like suction system and monitored individually. Under normal circumstances, all these inlets remain open until the detection device detects pollution/smoke. Selectively closing the inlet ports then allows the localizing and detecting of a fire zone. But the operation of this detection device also requires an extensive installation of suction lines to form a grid-like structure in order to ensure reliable detection of a fire source. Here as well, the disadvantage to this known device lies in the high installation outlay for the system of pipes.
Further known from DE 101 25 687 Al is a device for detecting and localizing a source of fire in one or more monitored areas. The device comprises a main sensor for detecting a fire parameter with an intake unit continuously feeding samples of the ambient air from the monitored areas through a line disposed with intake ports arranged in each monitoring chamber. One sub-sensor each is thereby provided on or in the vicinity of at least one suction opening per monitored area, which is switched on by a switch-on signal transmitted by a controller in accordance with a detection signal emitted by the main sensor. The switched-on sub-sensor thereby serves in the detecting of the source of the fire and thus for localizing the fire source from the plurality of monitored areas. This device known from the prior art has the disadvantage that due to the number of sub-sensors employed, the costs associated with the fire detecting device are relatively high and furthermore necessitates a relatively complex wiring of the sub-sensors when installing the device.